Prefabricated concrete panels have been used in a variety of building applications to provide a relatively easily assembled and relatively inexpensive building. Many of the prior construction systems have a disadvantage in that they require that at least basic horizontal and vertical structural components be constructed to act as a frame to which the prefabricated panels can be attached.
U.S. Pat. No. 3,683,578 to Zimmerman, issued Aug. 15, 1972, discloses a concrete building arrangement which purportedly eliminates the requirement to pre-form the vertical support structure. In Zimmerman's arrangement, wall panels are aligned by co-operating guide means on the base of the panels and on the foundation with which the panels co-operate. While alignment of the base of the wall panels is provided by the co-operating guide means, alignment of the upper portion of the panel is achieved by a bolt means, which co-operates with reinforcing bars within the panels. The co-operation between the bolts and the bars also acts to secure adjacent panels together. One disadvantage of Zimmerman's arrangement is the requirement to preform a concrete foundation slab to support the panels.
Another disadvantage of many prior art construction methods is that they have limited utility in the construction of basements. When concrete panels are used the basement wall tends to shift laterally where the panels join during backfilling. This is a particular problem where the panels meet to form a corner. The result is that the concrete panels used in basement construction must be secured to pre-poured concrete foundation pads in a manner to prevent lateral movement. The need to pour a foundation pad reduces the advantage sought to be gained by using prefabricated concrete panels.
U.S. Pat. No. 5,493,838 to Ross, issued Feb. 27, 1996, discloses a method of constructing a basement from prefabricated concrete panels which purportedly eliminates the requirement of pre-pouring a concrete foundation pad. In Ross' method, the building site is first excavated and footings are positioned in the excavation to define the outline of the building. Prefabricated floor panels may be placed between the footings. Once the footings are in place, prefabricated, freestanding concrete corner sections are placed on the footings where it is intended that the building have a corner. A plurality of concrete panels can then be joined end-to-end between the corner sections to complete the peripheral wall. This reference does not teach a system that facilitates the construction of a second floor of a building.
In U.S. Pat. Nos. 4,751,803 and 5,656,194, there are described concrete wall panel systems wherein concrete beam and stud members are assembled to form a panel. Such panels are then arranged to form outer walls for a building. However, these references do not teach a concrete wall panel system wherein the complete panel is formed simultaneously as a unitary structure.